When producing future generations of animals of the highest genetic merit or elite genomic value, a critical selection of potential breeding animals must be made. Only germplasm from the most elite animals can be harvested and used at the genetic nucleus level. Germplasm can include but is not exclusive to gametes such as sperm and oocytes, but also embryos, fetuses, neonates and somatic cells or tissues from living animals.
To that end, genomic testing in the livestock industry has become a valuable tool in evaluating young animals and in increasing genetic progress by increasing the accuracy of selection and decreasing the generation interval. Typically, young animals are genomically tested shortly after birth or as young adults, therefore requiring that significant resources be devoted to supporting the mother during fetal gestation even though the genetic merit of the offspring is unknown.
Embryo transfer is a procedure that follows fertilization (either in vitro or in vivo) and involves the transfer of one or more embryos, from a test tube or the biological mother, to a recipient animal for gestation and birth. Embryo transfer is another tool for increasing genetic progress, since it increases selection intensity by allowing the use of a smaller number of elite females as mothers of many offspring and may also decrease the generation interval in the case where female egg donors are made to ovulate sooner than they normally would be able to give birth. In the livestock industry, the major expense portion of any embryo transfer program is the cost and maintenance of recipient animals into which the embryos are placed for gestation, which may limit its application.
Cloning is yet another tool that can be used to increase genetic progress by increasing the accuracy of selection. See Bousquet and Blondin, “Potential Uses of Cloning in Breeding Schemes: Dairy Cattle,” Cloning and Stem Cells, vol. 6, no. 2, abstract (2004). Cloning can also be used to speed up genetic dissemination of genes from animals of exceptionally high genetic merit to the commercial population. Id. The applicability of cloning has to date been limited, however, due to the lag time before a cloned animal can participate in a breeding program. Id. at 193.
Accordingly, there is a need to increase genetic progress and/or genetic dissemination by increasing and improving the use of genomic testing, embryo transfer and cloning in the livestock industry, as well as to reduce the costs and maintenance associated with maintaining recipient animals used in embryo transfer.